When hair fibers are illuminated by a light source, part of the incident light is reflected on the surface of the hair - specular component - and part is transmitted through to hair fiber and reflected on the back surface - chroma component -. |
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Hair fibers present a natural birefringence, which orientation axis is aligned with the fiber axis. Using the birefringence polarization signature, RUMBA measures the birefringence information and therefore the orientation of the hair fiber. |
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